1. Field of the Invention
The invention relates to a ventilator cover for exhaust ventilation of roofs in the ridge, hip or arris area, with a preferably plastic ventilator cover body and a sealing element, the sealing element having a shape approximating that of a wedge in cross section and a sealing element body consisting of plastic foam. Furthermore, the invention relates to a sealing element of the aforementioned type and a process for producing, on the one hand, a ventilator cover, and on the other, a sealing element.
2. Description of Related Art
Ventilator covers have been known for some time. They are located in the ridge, hip or arris area of a roof in order to prevent possible damage by moisture formation. Using a ventilator cover with ventilator cover bodies which have air passage openings, for the corresponding incident flow a negative pressure below the ventilator cover is generated which leads to ventilation of the roof space. As a result of this function, these ventilator covers are also called exhaust ventilator covers. To guarantee effective exhaust ventilation in the roof area, a good seal between the roof, on the one hand, and the ventilator covers, on the other, is necessary. For this reason, wedge-shaped sealing elements are used which have a sealing element body formed of a plastic foam. These sealing elements, which are also called foam sealing wedges or foam filter wedges, are already known from German Utility Model Nos. 84 16 540, 85 27 095, 87 12 892, 87 13 110, 87 17 115, and 89 14 943, Published German Application Nos. 35 11 798, 38 06 683, 38 12 305, and 38 36 334, and German Patent No. 36 15 01.
Ventilator covers of this type are generally attached in the middle on the ridge beam of a roof. The wedge-shaped sealing elements, which have high flexibility due to their sealing element body being made of plastic foam, are pressed wit their tips against the roof covering; this, then, leads to the aforementioned sealing. If flow takes place against or over the ventilator covers, a negative pressure develops in the ridge area of the roof, as already mentioned.
The ventilator cover bodies of known ventilator covers are usually produced by extrusion or injection molding. In extrusion, post-treatment is still necessary to firm the specific shape of the ventilator cover body; this is not necessary in discontinuous injection molding.
The sealing elements which have a sealing element body of plastic foam are generally produced by extrusion. In doing so, the plastic used is normally foamed using a blowing agent as it leaves the extrusion tool. During extrusion, relatively long foam slabs of great width and comparably low thickness are continuously produced. These molded articles generally have low dimensional accuracy. Upon subsequent cooling of the extruded molded article, it can collapse at various points; this is the result of condensation of the blowing agent at these points. Condensation of the blowing agent is undesirable since it leads to wavy surfaces on the molded article, and further, increases the waste which is formed in relatively large amounts anyway. This results from the fact that wedge-shaped sealing elements of comparatively high dimensional accuracy are subsequently cut from the completely foamed molded article.
The sealing elements cut in a wedge shape are each cemented to the bottom of the ventilator cover body to produce the ventilator covers. Since the ventilator covers generally have a shape which is arched downward, the sealing elements, in the mounted state of the ventilator covers, are generally not visible. Still, the outside surface of the sealing elements is exposed to weathering and UV radiation. After some time, this can lead to damage to the plastic foam, and thus, to sealing element leaks. As a result of leaks, the sealing action of the sealing element is reduced; this is associated with poorer ventilation and penetration of moisture into the interior of the roof.